Electrochemical recorder



Se t. 13, 193& E. B. D. MACKENZIE ELECTROCHEMICAL RECORDER Filed Nov. 29, 1935 2 Sheets-Sheet 2 InvenZZr FIG.2.

Patented Sept. 13, 1938 2429.176 ELnc'rnoonEMicAL nncormsn Edward Briggs Drake Mackenzie, Portland, England, assignor to Henry Hughes & Son Limited, London, England, a corporation of Great Britain Application November 29, 1935, Serial No. 52,264 In Great Britain December 3, 1934 3 Claims.

This invention relates to recording apparatus in which a permanent record is obtained by means of electro-chemical action on suitable sensitized paper, and in previous recording apparatus of this type a roll of dry paper has been sensitized by drawing it over a wick or other moistening device which dips into a tank containing a suitable solution such as potassium iodide and starch, or the paper has been sensitized and subsequently dried and then moistened, as required, with water.

The paper moistened in this manner is drawn over a writing table and a stylus is arranged to traverse the paper and make electrical contact through the sensitized paper to the writing table when a record is to be produced on the paper.

In electro-chemical recorders of this type in which the paper or other material has to pass over moistening or sensitizing means, apart from the'disadvantage of having to employ these necessary adjuncts, there is difiiculty in ensuring at all times the required degree of moisture for best working, as, if the speed of travel of the sensitive material is changed it may be necessary to readjust the moistening means and such adjustment may require considerable and prolonged manipulation.

Furthermore, the time required for the moistened and sensitized material to reach the stylus track also makes it cliificult to obtain records directly the apparatus is started.

In the present case the electro-chemical recorder employs a recording strip in a pro-sensitized and pre-moistened condition, this presensitized and moistened strip being stored in a suitable air-tight container until required for use. The recording strip is sensitized and moistened by any suitable means, such as by draw.- ing the dry strip by means of rollers through a tank containing a solution, for example, of potassium iodide and starch,- the requisite degree of moisture being controlled by adjustment of the pressure between the rollers, such as by the employment of suitable springs, and thesensitized strip in its moist condition is rolled on to a-spool and stored in an air-tight container. When required for use the prepared strip is re-' moved from the storage container and mounted in a casing, which is nearly air-tight and forms part of the recording apparatus. The strip is drawn from the spool through a slot in the casing between a roller and a soft rubber pad which tends to seal the slot and over a writing table by means of feed rollers between which the strip is passed, one of the feed rollers being driven while the other is free or geared to the driven roller. After passing through the feed rollers the strip may be rewound on to a spool driven by any suitable means.

If desired, a heater maybe fitted in any suit- 5 able position to dry the strip before it is rerolled.

In order to enable a record to be obtained immediately after starting the recorder, one of the feed rollers may be provided with a knob 10 for rotating it by hand and a ratchet feed or any other type of free wheel drive, e. g., a coiled spring, provided between the roller and its drive to enable the roller to be turned more rapidly by hand than it is normally driven so that the 1 portion of the strip which is outside the casing and may, therefore, have become dry before the recorder is set in operation may be rapidly drawn away and a fresh portion of the moist and sensitized strip withdrawn from the casing. 0

One suitable construction of a portion of an electro-chemical recorder which comprises the present invention is illustrated in the accompanying drawings in which- I Fig. 1 is a front elevation of a container for the pie-sensitized and moistened strip and of the means for drawing the recording strip beneath the stylus; although the recording strip I itself is not shown in this view. 7

Fig. 2 is a sectional elevation through the airtight container and the feed rollers and a device for drying the moist recording strip.

The recorder is provided with a recording stylus I which is attached to an arm 2 and this arm may be moved by any suitable means (not shown) so that the stylus is caused to traverse the recording strip. Preferably the stylus is moved in a circular path by the arm 2 being attached to a rotating carrier, but, if desired, the stylus may be reciprocated across the paper in a straight line or may even be stationary.

The recording strip which the stylus marks is supported by a suitable writing table which in this case is the 'cover 3 of the container 4 for the moist sensitized recording strip 5 which is rolled on a spool 6 supported in brackets I within the container 4 so thatthe spool can rotate and these brackets I are conveniently secured to the cover 3 of the casing 4 which is made practically air-tight except for a slot of small dimensions through which the strip 5 passes out of the casing as it is unwound from the spool 6. On leaving the casing 4 the strip 5 passes between a roller 8 and a soft rubber pad 9 which tends to seal the slot and the strip 5 then passes across the stylus track and between the feed roilers I and II, which are suitably pressed together by a spring l2 to grip the strip.

The roller Ill is driven through a worm wheel l3 and worm ll which is driven through a flexible shaft l5 from the drive which rotates the stylus in the case where the stylus is moved in a circular path. The two rollers are geared together by gear wheels l6 and interposed between the worm wheel l3 and the roller 10 is a free wheel device or ratchet device which in this case is a coiled spring ll surrounding the shaft on which the roller I0 is supported so that if it is necessary to withdraw quickly a portion of the recording strip when the recorder is started, owing to the exposed portion of the strip having dried before the apparatus is started, the roller I can be rotated in advance of its drive by means of a hand knob ii, the spring I! unwinding suffi ciently to enable the rollers to be turned faster than they are normally driven.

After passing between the feed rollers l0 and II the strip 5 preferably passes between two electrical heating elements i 9 carried in a suitable holder and bracket so that the 'moist strip can be dried before being rolled up for storage purposes.

The air-tight container 4 and the feed rollers II and II are supported between side pieces 2! projecting from a back plate 22 and the cover 3 of the casing is pivoted on the side pieces 21 in such a manner that the cover 3 can be dropped downwardly before being swung open. For this purpose the cover 3 has pivot pins 23 projecting from its sides and movable in vertical slots 24 cut in the side pieces 2| and near the upper edge of the cover 3 two more pins 25 project through L-shaped slots 26 cut in the side pieces 2!. The pins 25 have attached to them links 2'1 which are pivoted at their other ends by pins 28 on levers 23 pivoted on pins fixed to the side pieces 2 I. These levers 29 are normally retained in their upright positions by the springs 3|. When it is desired to open the casing, the upper ends of the levers 29 are pulled outwardly and the levers turn about their pivot pins 30 and the links 21 pull the pins 26 downwards which causes the cover 3 and the brackets I attached to it and the spool 8 to drop so that the pivot pins 23 then bear on the bottom of their slots 24. This downward movement of the cover 3 also brings the pins 25 to the horizontal part of the L-shaped slots 26 and the pins 25 are therefore free to move out of the side pieces 2| as the cover 3 swings outwardly and downwardly on its pivot pins 23.

The link 21 and the part of lever 29 between the pivots 28 and 30 form a toggle which, in the position shown, is at its dead centre or rigid position, with link 21 and the straight part of lever 29 in alignment so that the toggle is rigid and holds the cover firmly closed. When the casing is to be opened the lever 29 is swung clockwise (as viewed in Fig. 2) about its pivot 30 and the toggle therefore collapses and the out ward and downward movement of the pivot pin 28 causes the pins 23 and 25 to move down in their slots, and the continued outward movement of pin 23 causes pin 25 to move along the short horizontal part of slot 28 so that the cover is swung open.

The stylus is connected to a recording circuit while the cover 3 of the casing or the roller I is also connected to the recording circuit so that when an electric current is sent through this recording circuit a chemical action takes .place on the sensitized paper at the point where .the stylus is in contact with it, resulting in a mark being made on the paper strip thus forming a permanent record. The distance of the mark from the edge of the paper can be used as a measure of the time interval between any fixed datum and the instant of the passage oi the electric current. In the case of echo sounding recorders the distance of the mark from the edge oithe paper, or a datum line irom which the stylus commences its travel, forms a record of the depth determined by the echo sounding gear.

What I claim as my invention and desire to secure by Letters Patent is:

1. In an electro-chemical recording device of the type employing a paper strip and a traversing stylus, a asing, a spool containing 9. rolled strip oi presensitized paper within said casing, means within said casing for supporting said spool to enable it to rotate, a slot formed in the casing to permit egress of the strip, feed rollers for withdrawing the strip, a mechanical drive for rotating one of the feed rollers, a yielding Ireewheel device interposed in the drive to said roller, and a hand knob for rotating the roller in advance of the drive to enable the paper strip to be rapidly withdrawn.

2. In an electro-chemical recording device, a casing containing a recording strip, feed rollers for withdrawing the strip from the casing,-a mechanical drive for rotating one of the feed rollers, said drive including a gear rotatable freely on the shaft of said roller but coupled thereto by a free wheel device comprising a coiled spring surrounding the shaft to transmit the mechanical drive from the gear to the shaft, and a hand knob secured to the end of said shaft for rotating the roller in advance of the mechanical drive.

3. In a device 0! the character described, a paper containing casing having a slot for withdrawal of paper therefrom, a pair of inter-geared feed rollers to receive and advance paper from said container, a drive gear, a driven gear meshing with said drive gear and freely mounted about one of said feed rollers, a coil spring secured to said driven gear and loosely wound about a portion of said one feed roller in the direction opposite to the direction of feed rotation thereof whereby said spring tightens about and transmits the force of said driven gear to said one roller in one direction only, and a knob on said one roller to permit manual rotation of said one roller in the direction of feed, said coil spring slipping when thesaid one roller is manuall rotated in the direction of feed.

EDWARD BRIGGS DRAKE MACKENZIE. 

